Vlad almost always shows up within the first few nights of any new household I play. I think it is coded in the pack to happen so that you have an "in" with him if you want to pursue the pack features.
Unless I'm looking to embrace vampires or vampirism with the household, I just ignore him. He never returns if you ignore him on the first visit. Though there is a mod that re-enables vampire break-ins if you actually want that in your game.